Automotive type air conditioning systems comprise a compressor mounted in the automotive engine compartment. The compressor includes a housing that contains pumping elements for pressurizing a refrigerant gas in the automotive air conditioning system. The pumping elements may consist of double-acting, axially disposed piston and cylinder mechanisms driven by a swash plate carried by a torque input driveshaft.
Other compressors, such as the compressor disclosed in my copending patent application Ser. No. 001,600, filed Jan. 7, 1993, entitled "Scroll-Type Compressor Having Unidirectional Rotor", may comprise a pair of scrolls, one of which is fixed and the other of which follows an orbital path relative to the fixed scroll. The scrolls have wraps that define pressure chambers between tangential contact points between the wraps of the individual scrolls.
Regardless of which type of pumping elements is used, it is necessary to drive the pumping elements by a torque input driveshaft, sometimes referred to as the rotor shaft. The driveshaft, in turn, is adapted to be coupled to a drive pulley by means of a selectively engageable electromagnetic clutch.
It is common practice to journal the armature for the electromagnetic clutch and the drive pulley on a fixed sleeve that forms a part of the compressor housing. This arrangement is shown for example in prior art U.S. Pat. No. 4,718,526. The clutch and pulley arrangement of that patent may be used for driving the scrolls of a scroll-type compressor as disclosed, for example, in U.S. Pat. Nos. 4,730,988 and 4,696,630.
My copending patent application identified above is assigned to the assignee of my present invention.
In a typical prior art bearing arrangement for a clutch and the drive pulley for a compressor, the shaft bearings are located within a fixed sleeve. This requires careful machining of a shaft bearing opening so that it is precisely concentric to the axis of the rotor shaft. Further, the same fixed sleeve is adapted to support the inner race of a bearing for the pulley and the armature of the electromagnetic clutch. This requires a separate precision machining operation.
It is necessary in such prior art designs for special steps to be taken during the machining operation to precisely locate the bearing center for the pulley and clutch assembly with respect to the bearing center for the rotor shaft assembly.
This makes it necessary to effect costly tolerance controls during the manufacturing operation. It also makes it necessary to provide separate bearings for the shaft and for the pulley and clutch assembly.